I'd actually encourage you to make much larger upper levels. Those shelves are so small and barely have room for bunny to stretch out ...and only if he faces the right direction. Not trying to offend, but they are really little more than landing platforms.
Unless a particular one is being used as just a step to an upper level, each "shelf" should be a minimum of 2 grids x 2 grids in size.
I also notice that you've used plenty of those connectors that come with the grids. They have been known to randomly pop off with a persistent bunny. If they are reinforced with zip ties, fine. I just don't bother with them since I'm using ties anyway. But what that allows me to see in your photo is that there seems to be a lack of doorway openings on the upper levels as well. When building your cage, you want to be sure that you have a way to reach every place that bunny can sit. If he is feeling ill and hides in an upper corner, you'll need to be able to get to him without dismantling your cage.